DE4130371A1 - TORQUE CONTROL SYSTEM FOR DRIVED WHEELS - Google Patents

Description

The present invention relates to a torque control system for driven wheels according to the preamble of the claim 1.

It is known the output torque of an internal combustion engine in a train control system as well as from this estimated output torque and a reduction ratio between the internal combustion engine and the driven one Wheel to estimate a torque of the driven wheel (see see JP-OS 31 831/88).

It has also become known the torque of a driven one Wheel considering one by one Torque converter in a vehicle with an automatic transmission to determine the increased torque amount and a torque reduction device for the driven wheel too actuate when the torque of the driven wheel is one exceeds the predetermined value (see JP-OS 1 48 629/89).

In the latter system, the output torque of the driven wheel based on an input current / output speed ratio of the torque converter is calculated and prevents the driven wheel from slipping if whose torque exceeds a required value. An actual one Slipping of the driven wheel is however caused by caused an excess of its torque, which with an increase in the output torque of the Internal combustion engine increases. It is therefore a certain time delay from a moment when the output torque of the internal combustion engine is increased up to a moment in which the torque of the driven Wheel is increased. For this reason the driven one arrives Wheel in a slipping condition when its torque is the required Amount exceeds even if the torque of the driven wheel is controlled. Finally it happens  an on / off feedback control for the required torque, which makes it difficult for the torque to drive it Control the wheel in a suitable manner.

The present invention is based on the object a torque control system for driven wheels with one between an internal combustion engine of a motor vehicle and a torque converter provided a driven wheel and a device for reducing an output torque the driven wheel in the event of excessive slipping of the driven wheel for a calculation of an effective Torque for the driven wheel (this is Within the scope of the present invention a transferable Torque) an influence of the amplification of the torque to be taken into account by the torque converter, which ensures is that a proper transferable torque calculated to find a suitable starting tax figure can be.

This task is the beginning of a torque control system mentioned type according to the invention by the features of characterizing part of claim 1 solved.

According to the torque ratio of the torque converter in the calculation of the fed to the driven wheel Torque is taken into account. It is therefore possible a suitable transferable torque based on a to calculate the correct torque supplied to the driven wheel and thus an overload in the control of the Avoid slipping of the driven wheel.

According to developments of the invention, which is the subject of Subclaims are possible, it is possible to use one for the calculation a transmissible torque of the driven wheel necessary Correctly calculate excess torque.

An output speed and a torque ratio can also be used  of the torque converter in a control convergence state based on the speed of the driven Rades are estimated, with convergence occurring when a control variable based on a correct the driven Wheel supplied torque is generated. Therefore the control variable at such an estimated torque ratio continue to be calculated correctly, resulting in an improvement of control accuracy.

Another possible solution according to the invention of the above specified object is the subject of claim 4.

It is not necessary to apply an excess torque calculate when the torque of the driven wheel in on compared with a given threshold in a known manner becomes. It can therefore be a value of the driven wheel supplied torque based on only the estimated torque ratio of the torque converter estimated be based on the speed of the driven Wheel (target speed of the driven wheel) at the time is calculated when the driven wheel slips converges. It is therefore possible to prevent the driven from slipping Wheel in a simple manner taking into account the To control the torque ratio of the torque converter.

The invention is described below with reference to the figures of the Drawing illustrated embodiments explained in more detail. It shows

Figure 1 is a schematic representation of the structure of a vehicle with a control system according to the invention.

Fig. 2 is a block diagram of an electronic control unit;

Figs. 3A and 3B is a flow chart for explaining the contents of control in the electronic control unit;

FIGS. 4A and 4B, a Flußdiagrmam a subroutine of a step S 3;

Fig. 5 is a flowchart of a subroutine of a step S 25;

Fig. 6 is a timing diagram showing a change of a speed reduction ratio M _{G / R} during switching;

FIGS. 7A to 7D is a flowchart of a subroutine of a step S 27;

Fig. 8 is a diagram showing a gain characteristic of a torque converter;

Fig. 9 is a flowchart of a subroutine of a step S 28;

FIG. 10 is a diagram showing the relationship between a quantity and a size τ e _INIT, λ;

11 is a diagram showing the relationship between a quantity Ev and a size L _MINIT. and

Fig. 12 is a flowchart of a subroutine of a step S33.

An embodiment of the invention is described below of the figures.

Fig. 1 shows schematically the structure of a vehicle with a control system according to the invention. The vehicle includes a pair of wheels Wr driven by an internal combustion engine E and a pair of idler wheels Wf. A speed detector 1 for the driven wheels and a speed detector 2 for the idler wheels are mounted on the respective wheels to detect the speeds Vw and Vf to detect driven wheels Wr or the rotating wheels Wf. The internal combustion engine E is provided with a speed detector 3 , which comprises a gear and an electromagnetic pickup for detecting the speed Ne of a crankshaft of the engine E. Furthermore, the motor E is provided with a transmission position detector 5 for detecting the shift position of an automatic transmission 4 having a torque converter. In an intake pipe 6 of the internal combustion engine E there is an intake pipe internal pressure detector 7 for detecting the internal pressure P _B in the intake pipe and a throttle valve 9 connected to a pulse motor 8 , which can be opened and closed by the engine. At the rear end of the intake pipe 6 in the direction of flow, a fuel injection valve 11 with a fuel cut-off device 10 is provided. Furthermore, an atmospheric pressure detector 12 for detecting the atmospheric pressure P _A and a water temperature detector for detecting the temperature T _W of cooling water in a water container are provided. The speed detector 1 for the driven wheels, the speed detector 2 for the idler wheels, the speed detector 3 , the gear position detector 5 , the intake manifold internal pressure detector 7 , the pulse motor 8 , the fuel cut-off device 10 , the atmospheric pressure detector 12 and the water temperature detector 18 are all with one Microcomputer formed electronic control unit U connected.

Fig. 2, the electronic control unit U is for arithmetic processing of the recorded detector signals the individual detectors in accordance with a control program for driving the throttle valve 9 through the Inpulsmotor. 8 The electronic control unit U contains a central processing unit (CPU) 13 for performing the aforementioned arithmetic processing, a read-only memory (ROM) 14 containing the control program and data, for example in the form of tables, a working memory (RAM) 15 for intermediate storage of the detector signals from the detectors and the Results of the arithmetic calculation, an input part 16 with which the detectors, ie the speed detector 1 for the driven wheels, the speed detector 2 for the idler wheels, the speed detector 3 , the gear position detector 5 , the intake pipe internal pressure detector 7 , the fuel cut-off device 10 , Atmospheric pressure detector 12 and the water temperature detector 18 are connected, and an output part 17 , to which the pulse motor 8 is connected.

The electronic control unit U processes the detector signals received via the input part 16 and the data stored in the read-only memory 14 in the central processing unit 13 in accordance with the control program and finally controls the pulse motor 8 via the output part 17 . With this, the closing of the throttle valve 9 is controlled so that the output torque of the engine E is changed and the torque for the driven wheels is controlled to an optimal value to restrict excessive slipping of the driven wheels Wr.

The type of control for the driven wheels carried out in the electronic control unit U is described in detail with reference to FIGS. 3 to 12. A flow chart according to FIGS . 4A and 4B shows a subroutine corresponding to a step S 3 in FIG. 3A, while flow charts according to FIGS . 5, 7A to 7D, 9 and 12 subroutines corresponding to steps S 25 , S 27 , S 28 and S 33 according to FIG. 4A.

According to Fig. 3A a signal from the Kraftstoffabschalteinrichtung 10, in a step S 1 based on decision whether or not the fuel is off. In a step S 2 , it is decided on the basis of a detector signal from the speed detector 3 whether the speed Ne is equal to or less than 1500 revolutions per minute or not. If it has been decided that the fuel is to be switched off and Ne is greater than 1500 revolutions per minute, the processing proceeds to step S 3 . In other cases, processing proceeds to step S 4 . The fuel cut-off is carried out when it is decided that a slipping V _{E of} a driven wheel, that is, from the subtraction of a target speed of the driven wheels V _RP , which is a function of the speed V _V of the rotating wheels generated by the speed detector 2 for the rotating wheels Wheels, of which the speed V _W generated by the speed detector 1 for the driven wheels for the driven wheels difference is sufficiently large and that the driven wheel Wr slips excessively. The aforementioned quantities V _E and V _RP are given by the following equations:

V _E = V _W -V _RP

V _RP = F (Vv) = K · Vv

where K is a constant.

If the fuel is switched off and a condition Ne <1500 revolutions per minute is not realized, a throttle valve feedback cycle, which is a function of the rotational speed Ne of the internal combustion engine E, is sought on the basis of a data table in step S 4 . In a subsequent step S 5 , it is decided whether the feedback cycle is carried out or not. If this is the case, then in a step S 6 control coefficients K * _THP , K * _THI and K * _THD for a PID feedback control of the throttle valve opening size are defined in order to carry out the PID feedback control. It is then determined in a step S 7 whether the throttle valve feedback was carried out the last time or not. If this is the case, an I-quantity R ^N _{THFBI is calculated} based on the following formula:

R ^N _THFBI = R ^N-1 _THFBI -K ^N * _THI · V _E

In this equation, there is a minus sign in the second term on the right because the quantity V _{E takes on} a positive value of greater than zero. On the other hand, if the answer S 7 is NO, the initial throttle valve _{opening quantity} R _THINIT , which will be described below, is replaced in a step S 9 by the quantity R ⁰ _THFBI . If the I size R _{THFBI is} found, the I size is limited in steps S 10 to S 13 . Specifically, step S 10 will decide whether or not the size R _{THFBI is} equal to or larger than a throttle valve _opening size R * _TO , whereby a component corresponding to friction in the internal combustion engine E is compensated for. If the answer is NO, then the value R * _TO in step S 11 is replaced by the value _THFBI. In step S 12 , a decision is made as to whether or not the value R _{THFBI is} equal to or less than the throttle valve _opening value R * _WOT corresponding to a throttle valve _opening value of 80% at which the internal combustion engine generates the maximum torque. If the answer is NO, then the value R * _WOT is replaced in step S 13 by the value R _THFBI. Then, in a step S 14, a P quantity R ^N _THFBP according to the equation

R ^N _THFBP = K * _THP · V _E

and then in a step S 15 a D quantity R ^N _THFBD according to the equation

R ^N = K _{THFBD THD} · _E

calculated.

Then in a step S 16 a feedback control variable R _THFB according to the equation

R _THFE = R _THFB1 -R _THFBP -R _THFBD

calculated, in which the second and third terms are provided with a minus sign on the right because V _E also assumes a positive value of greater than zero, the feedback control variable R _{THFB being limited} in steps S 17 to S 20 . Specifically, it is decided in a step S 17 whether or not the size R _{THFB is} equal to or larger than the size R * _TO mentioned above. If the answer is NO, the size R * _{TO is replaced} in step S 18 by the size R _THFB . In step S 19 , a decision is made as to whether the size R _{THFB is} equal to or smaller than the size R * _WOT . If the answer is NO, the size R * _{WOT is} replaced by the size R _THFB in step S 20 .

In steps S 1 and S 2 it was decided that the fuel is switched off and Ne <1500 revolutions per minute, wherein in step S 3 the subroutine shown in the flow chart according to FIGS . 4A and 4B is carried out by an interruption of 10 ms . First, in a step S 21 , a decision is made as to whether or not a last fuel cut flag F _{F / C} is zero. If this is not the case, ie if the fuel is switched off, a decision is further made in a step S 22 as to whether or not a throttle valve release _indicator F _{THINIT is} equal to zero. If the answer is YES, the processing proceeds to a step S 25th If the answer is NO, processing proceeds to step S 33 based on the decision that the initial throttle _{opening amount} R _{THINIT has} already been found. If it has been decided in step S 21 that the fuel cut-off indicator F _{F / C} is zero, ie if the fuel cut-off has now been carried out for the first time, a throttle valve release counter is set to 100 ms in step S 23 and started. In a next step S 24 , the throttle valve release _indicator F _{THINIT is reset} to zero and the process proceeds to step S 25 .

In step S 25 , an output torque TQ _{OUT of} the internal combustion engine is calculated as a function of the intake pipe internal pressure P _B and the rotational speed Ne of the internal combustion engine. Specifically, in a step S 101 according to FIG. 5, which represents a subroutine of step S 25 , a maximum torque TQ _{MAX of} the crankshaft when the throttle valve is fully open is sought from a data table corresponding to a running speed Ne of the internal combustion engine E. Then, in a step S 102, an internal intake manifold pressure P _BWOT when the throttle valve is fully open and an internal intake manifold pressure P _{BWOT are searched} for from a data table in accordance with the rotational speed Ne of the internal combustion engine E when it is _{not loaded} . Then in a step S 103 a water temperature correction factor K _{TWTQ is sought} from a data table based on an output signal from the water temperature _detector 18 and in a step S 104 an atmospheric pressure correction factor K _{PATQ is searched} from a data table based on an output signal from the atmospheric pressure _detector 12 . In a step S 105 , the following linear interpolation _{equation introduces} the intake manifold internal pressure P _BWOT when the throttle valve is fully open and the internal intake manifold pressure P _BWOT when _{not charging} , which were searched for in step S 102 , and a running internal intake manifold pressure P _{B Intake pipe internal pressure} correction factor K _PBTW calculated:

K _PBTQ = (P _B -P _BNL ) / (P _BWOT -P _BNL )

It is then decided in a step S 106 whether or not an air / fuel ratio _flag F _{WOT has been} set. If this indicator is set, which corresponds to a normal operating condition, an air / fuel ratio _{correction factor} K _AFTQ with the value 1 is selected in a step S 108 . If the air / fuel ratio indicator F _{WOT is} not set, which corresponds to an operation with a small load, a predetermined value K _AFTQO (0.9) is selected in step S 107 as the air / fuel ratio _{correction factor} K _AFTQ . In a step S 109 , an output torque of the internal combustion engine corresponding to a running intake pipe internal pressure P _B is calculated by multiplying the maximum torque TQ _{MAX of} the crankshaft sought in step S 101 by the intake pipe internal pressure correction factor K _PBTQ calculated in step S 105 . The resulting value is multiplied with the searched in step S 103 water temperature correction factor K _TWTQ, the searched in step S 104 atmospheric pressure correction factor K _PATQ and the searched in steps S 107 and S 108 air / fuel ratio correction coefficient K _AFTQ, whereby a running engine output torque TQ _{OUT is} estimated. Instead of estimating the internal combustion engine output torque TQ _OUT using the intake manifold internal pressure P _BWOT when the throttle valve is fully open and the internal intake manifold pressure P _BNL when not loaded, the maximum torque TQ _{MAX of} the crankshaft can also be calculated using a linear interpolation equation from the at full opening Throttle valve and fuel quantities injected at idle are estimated.

The engine output torque TQ _OUT is estimated in step S 25 in FIG. 1A in the manner described above, but a certain time delay is caused until the engine output torque TQ _OUT changes after changing the operating state of the engine E because a certain Time is required until air detected in the intake pipe internal pressure detector 7 is drawn into the internal combustion engine E and compressed there and made to explode. For this reason, the engine output torque TQ _{OUT is} subjected to filtering in a next step S 26 according to the following equation:

where 0 <∝ <1 applies.  

The filtering causes the error caused by the above-mentioned time delay to be absorbed, as a result of which a correct internal combustion engine output _{torque OUT} is always estimated even in a transition period of the operating state of the internal combustion engine E.

Then, in a step S 27, a pseudo or intermediate inspection ratio M _{G / R is determined} when the automatic transmission 4 is shifted. This means that there is a time delay in the operation of a solenoid causing the changeover in a period B and therefore the changeover is actually not carried out and the gear ratio G / R is kept at a value before the changeover, even if the start of the changeover is in a Position A is detected by changing a gear ratio signal generated by the gear position detector 5 according to FIG. 6. In a subsequent period C, the shift change is actually carried out so that the speed N / M is changed in a main circuit. During this time, the pseudo-reduction ratio M _{G / R} is gradually changed. If the shift change ends in a period D, the torque converter begins to change the speed of the internal combustion engine E, while at the same time a gear ratio G / R is realized after the shift.

FIGS. 7A to 7D show a subroutine of the step S 27 to calculate the pseudo reduction ratio M _{G / R.} In a step S 201 according to FIG. 7A, a difference dG / R between a current gear ratio G / R ^H and a last gear ratio G / R ^{N-1 is} calculated. It is decided in a step S 202 that the difference dG / R is not equal to zero (if a switching signal according to FIG. 6 is generated) and if it is decided in steps S 203 and S 204 that a switching delay flag F _wait and a shift change flag F _sft , which will be described below, are not set (if the switching signal has been newly generated), a preparation to be described below is carried out in order to prepare an actual switching change. Specifically, the last gear ratio G / R ^{N-1 is defined} as the pseudo-reduction ratio M _{G / RST} to be held in a step S 205 and the current gear ratio G / R ^{N is defined} as the pseudo-reduction ratio M _{G / Rfin} after the shift change is completed in a step S 206 . It is then decided in a step S 207 whether the difference dG / R is positive or negative. Depending on this result, a switching delay timer t _wait 0 for an upshift and a switching delay timer t _wait 1 for a downshift are changed in steps S 208 and S 209 . Then, in a step S 210, a shift delay timer t _wait set and started in a step S 210 (entry into the period B in Fig. 6); In a step S 211 , the held pseudo-reduction ratio M _{G / RST is determined} as the pseudo-reduction ratio M _{G / R.} In a step S 212 , a shift change timer t _{sft is} set. The switching _delay flag F _{wait is} set in a step S 213 and a switching change flag F _{sft is} reset in a step S 214 . If the switching flag F _sft is 1 in steps S 204 and S 215 , this indicates that the switching signal was newly received during the switching change. In this case, the pseudo-reduction ratio M _{G / R} is determined in a step S 216 as the held pseudo-reduction ratio M _{G / RST} at the last shift change.

If the answer in step S 202 is YES, that is, if the switching signal is not generated, the processing proceeds to step S 217 in FIG. 7C. If the shift delay indicator F _{wait is} equal to zero, this means that the shift change is not carried out, the current gear ratio G / R ^{N being defined} as the pseudo reduction ratio M _{G / R} in a step S 218 . On the other hand, if the switching delay flag F _wait is 1 in step S 217 , this means that the switching change is being carried out. If the shift change indicator t _{sft is 0} in a next step S 219 , time compensation of the time delay timer t _{wait is} waited for in step S 220 and the shift change indicator F _{sft is} then _set in step S 221 . Then a difference dM _{G / R} between the pseudo reduction ratios M _{G / Rst} and M _{G / Rfin is calculated in} accordance with steps S 205 and S 206 in a step S 222 . If it is decided in a step S 223 that an absolute value of the difference dM _{G / R is} smaller than the difference value R _{G / R} , then in a step S 224 a divided width N _{G / R is} obtained by a product of a constant A _{G / R1} Absolute value of the difference dM _{G / R} smaller than the reference value R _{G / R} , a cut width N _{G / R} is calculated in a step S 225 by a product of a constant A _{G / R} 2 and dM _{G / R.} If the cut width N _{G / R is} calculated in this way, the shift change timer t _{sft is started} in a step S 226 in order to enter the period C according to FIG. 6.

If the shift change flag F _{wait is set} in step S 221 in the sense described above, the decision in step S 219 is YES. If the absolute value of a difference between the pseudo reduction ratio M _{G / R} and the pseudo reduction ratio M _{G / Rfin} after the shift change is greater than the reference value B _{G / R} in step S 227 and the setting time of the shift change timer t _{sft has} expired in step S 228 , the pseudo reduction ratio M _{G / R is} increased by the cutting width N _{G / R.} In this way, during the shift change (in the period C in FIG. 6), the pseudo reduction ratio N _{G / R is} gradually increased or decreased by the cutting width N _{G / R} when the set time of the shift change timer t _{sft has} elapsed by the difference between that To compensate for pseudo-reduction ratios M _{G / RST} and M _{G / Rfin} . If the decision in step S 227 is YES and the shift change is completed (in point D in FIG. 6), the shift delay flag F _wait and the shift change flag F _{sft are deleted} in a step S 230 or S 231 . The pseudo reduction ratio M _{G / Rfin} after the shift change is determined in a step S 232 as the pseudo reduction ratio M _{MG / R.}

Processing returns to step S 28 in Fig. 4A. In this step, the engine output torque is _out in a the driven wheels fed _out torque for the driven wheels Wr transferred. In this case, the torque is amplified by the torque converter between the internal combustion engine E and the driven wheels Wr, and a torque ratio L _{MAT is} calculated for this amplification.

The calculation of the torque ratio in the torque converter is carried out in detail below. The torque converter transmits a driving force from a pump shaft, which represents the input shaft for a turbine shaft as the output shaft, by means of oil and serves to amplify the transmission torque. In a converter range in which the speed ratio e of the output threshold for the input shaft according to FIG. 8 is equal to or less than about 0.8 or less, the value of a transmitted torque ratio λ is increased in the range 1 <λ <2, but the torque λ in a coupling area in which the wire ratio e exceeds 0.8, held at 1 and no reinforcement is carried out.

Fig. 9 shows a method in which it is a subroutine of step S 28 and through which the torque ratio calculated _MAT L of the torque converter from the rotational speed of the engine E and the rotational speed Vw of the driven wheels. First, a speed ratio e _AT of the output shaft and the input shaft of the torque converter is calculated in a step S 301 . Specifically, the speed Nt of the input shaft of the torque converter is equal to the speed Ne of the internal combustion engine E, the speed Nt of the output shaft of the torque converter being given by the following equation:

where Rw means an effective tire diameter.

The speed ratio e _AT is therefore given by the following equation:

where K _EAT = 1000/60 · 2π · Rw.

If the speed ratio e _{AT of} the torque converter is determined in this way, it is compared in a step S 302 with a coupling speed ratio e _CUP (approximately 0.8) of the torque converter. If e _AT e _CUP (converter area), the speed ratio L _MAT is approximated in a step S 303 by a straight line (see FIG. 8) which falls with an increase in the speed ratio e _AT . The following relationship applies:

L _MAT = K _{LM1e AT} + K _LM2

where K _LM1 and K _{LM2 mean} a constant. If in step S 302 e _AT <as e _CUP (clutch range), on the other hand the speed ratio L _{MAT is} approximated in step S 304 by a given value L _MCUP (see FIG. 8).

If the torque ratio L _{MAT of} the torque converter is calculated in the manner described above, a torque _OUT supplied to the driven wheels is calculated in a step S 305 by multiplying the internal combustion engine output torque TQ _OUT subjected to the filtering described above, a transmission factor found in accordance with the output signal of the gear position detector KM, the pseudo-reduction ratio M _{G / R} described above and the torque L _MAT calculated according to the following equation:

_OUT = K _M · M _{G / R} · L _MAT TQ _OUT

Then, FIG, returning to the step S in accordance with the 29th 4A is a maximum value _EM of the slip change amount _E of the driven wheels in the last 100 ms and a maximum value * _OUTM of the wanted the driven wheels in the last 100 ms supplied torque * _OUT. Specifically, the torque * _OUT supplied to the driven wheels and the slip change amount _{E of} the driven wheels are temporarily stored in the read-only memory 15 , the maximum values _EM and * _OUTM in the last 100 ms from the stored value * _OUT of the torque supplied to the driven wheels and the value _{E of} the slip change amount of the driven wheels can be selected. The value _E is a value which results from differentiation of the slip value _{E of} the driven wheels, which is generated on the basis of the speed V _W of the driven wheels generated by the speed detector 1 for the driven wheels and that generated by the speed detector 2 for the idler wheels Speed value V _{V is} calculated for the idling wheels. It is then decided in a step S 30 whether or not a time of 100 ms has elapsed. If this is not the case, the value R * _TO described above is replaced in a step S 31 by the initial throttle valve _{opening value} R _THINIT . On the other hand, the answer at step S 30 is YES, a portable torque TQ _INIT (that is, a torque value of a consumed in the excessive slipping of the driven wheels Wr excess torque from the driven wheels supplied torque TQ * _OUT is obtained by subtraction), which is used for increasing the vehicle speed, is searched in a step S 32 from the maximum value V _{EM of} the slip change amount value of the driven wheels and the maximum value * _OUTM of the torque supplied to the driven wheels. The latter two values were found in step S 29 .

Then, in a step S 33, the initial throttle _{opening amount} R _{THINIT is} calculated, in which case it is necessary to find an estimated torque ratio L _MINIT by estimating a torque _{ratio of} the torque converter at the time when the throttle valve 9 except for the initial throttle _{opening amount} R _{THINIT is} closed. This estimate is made based on the target speed V _{RP of} the specified wheels. Then, the initial throttle _{opening amount} R _{THINIT is corrected} with this estimated torque ratio L _MINIT .

A method of calculating the estimated torque ratio L _MINIT will be described in detail below. In general, an input torque Tp in the torque converter is given by the following equation:

Tp = τ · (Np / 1000) ² (1)

where τ means a pump absorption torque.

A rewording of equation (1) using the speed ratio e (= Nt / Np) of the input shaft and the output shaft and the torque ratio λ (= Tt / Tp) of the The input shaft to the output shaft results in the following Equation:

Tp = Tt / λ = τ · [NT / (1000 · e)] ² (2)

On the other hand, the speed Tt and the torque Nt of the output shaft decrease using the transferable torque TQ _INIT and the target speed V _{RP of} the driven wheels given by the following equations:

Tt = TQ _INIT / G / R (3)

These equations (3) and (4) are given in the above Equation (2) used to create a new relationship for an e find, which gives the following equation:

Looking at the characteristic τ · λ in relation to e shows that an approximation by a linear or a quadratic equation is possible. Fig. 10 shows an example in which τ · λ by a linear equation for s can be approximated, resulting in following equation:

τ · λ = A · e + B (6)

Substituting formula (6) into formula (5) results in for e the following quadratic equation:

e² + 2Ev - 2 (B / A) Ev = 0 (7)

where the following further relationship applies:

Solving this quadratic equation results in positive value of e the equation:

A relationship is established between the speed ratio e (hereinafter referred to as the torque converter's estimated speed ratio e _INIT ) and the quantity Ev, which is a function of the target speed V _{RP of} the driven wheels and the transmissible torque TQ _IN for the specified wheels of equation (9), a relationship between Ev and the estimated torque ratio L _MINIT according to FIG. 11 can be realized, because a relationship between the estimated speed ratio e _INIT and the torque ratio ( _hereinafter referred to as the estimated torque ratio L _MINIT ) of the torque converter, which is obtained from the estimated speed ratio e _INIT , is known in the sense described above. Therefore, the estimated torque ratio L _MINIT can be _determined from a value of Ev that is a function of the target speed V _{RP of} the driven wheels and the transmittable torque TQ _{INIT of} the driven wheels.

This is described below with reference to a flow chart according to FIG. 12, which is a subroutine of step S 33 according to FIG. 4B. First, in a step S 402, a value for Ev (see equation 8) is calculated from the value Ke, the target rotational speed V _{RP of} the driven wheels and the transmissible torque TQ _INIT for the driven wheels if the value Ke (see equation 8), which is a function of the gear ratio G / R determined in a step S 401 on the basis of an output signal from the gear position detector 5 . If the value Ev is determined in this way, an estimated torque ratio L _{MINIT is} determined in a step S 403 from the context according to FIG. 11 and stored in the read-only memory. Then, in a step S 404, an initial throttle _{opening amount} R _{THINIT is calculated} according to the following equation:

where dTH / dTQ means a change in the throttle valve opening amount necessary to bring about a change in the unit torque of the crankshaft and which is stored as a function of the engine speed Ne. K _PA here means a correction factor which atmospheric pressure detector 12 is set on the basis of an output signal, to correct the information obtained during standard atmospheric pressure value dTH / DTQ.

If the initial throttle valve _{opening amount} R _{THINIT is determined} in this way, its minimum value is limited to R * _TO and its maximum value to R _WOT in the manner described using steps S 34 to S 37 in FIG. 4B. Finally, the throttle release _indicator F _{THINIT is set} to 1 in a step S 38 .

If the throttle valve feedback control is started again in a step S 9 , the value R _THINIT described above serves as the initial throttle valve _{opening amount} . Such an initial throttle valve _{opening amount} R _THINIT corresponds to a throttle valve _{opening amount} , which results in a torque which results from subtracting an excess torque consumed in the event of excessive sliding of the driven wheels from the transferable torque TQ _INIT for the driven wheels. This is used for a speed increase of the vehicle, ie the torque TQ * _OUT supplied to the driven wheels, whereby it is possible to cover the final throttle valve opening amount with a value that ensures an optimal slip size of the driven wheels.

Claims (4)

1. Torque control system for driving wheels (Wr) with a vehicle provided torque converter and a torque reduction means for reducing the output torque of the driven wheel (Wr) when the slip is excessive in between an engine (E) and a driven wheel (Wr), by
an arrangement (in U) for calculating the output torque of the motor (E),
an arrangement (in U) for calculating the torque supplied to the driven wheel (Wr) for the purpose of converting the engine output torque calculated by the engine output torque calculation arrangement (in U) into a torque supplied to the driven wheel (Wr) using the torque ratio of the torque converter,
an arrangement (in U) for calculating an excess torque consumed when the driven wheel (Wr) slips,
an arrangement (in U) for calculating the torque which can be transmitted between the driven wheel (Wr) and a road surface on the basis of output signals from the torque supply calculation arrangement (in U) and the excess torque calculation arrangement (in U) and
a control variable determining arrangement (in U) for calculating a control variable for the torque reduction device using the transferable torque. 2. Torque control system according to claim 1, characterized by a between the motor (E) and the driven Wheel (Wr) provided variable reduction gear and by calculating the excess torque the base of the slip change size of the driven Rades (Wr) and a reduction ratio of the variable Reduction gear. 3. Torque control system according to claim 1 and / or 2, characterized in that the torque reduction device for the driven wheel (Wr), an engine output torque control device is and an arrangement for calculating a target speed for the driven wheel, an arrangement for calculating a Target speed ratio at a time when the Speed reduction device for the driven Wheel (Wr) is controlled using the target speed of the driven wheel (Wr) as the output speed of the torque converter and an arrangement for Correction of the control variable for the engine output torque control device by the estimated torque ratio includes. 4. Torque control system with a torque converter provided between an internal combustion engine (E) of a vehicle and a driven wheel (Wr) and with a torque reducing device for reducing the output torque of the driven wheel (Wr) when its slipping becomes excessive, in particular according to claim 1, characterized by
an arrangement (in U) for calculating an output torque of the internal combustion engine (E),
a calculation arrangement (in U) for calculating a target rotational speed of the driven wheel (Wr),
an arrangement (in U) for calculating an estimated torque ratio at a point in time in which the torque reduction device for the driven wheel (Wr) is controlled, using the target speed of the driven wheel (Wr) as the output speed of the torque converter,
an arrangement (in U) for calculating a torque supplied to the driven wheel (Wr) for converting the calculated engine output torque into a torque supplied to the driven wheel (Wr) using the estimated torque ratio and
a control quantity setting arrangement (in U) for calculating a control quantity for the torque reduction device for the driven wheel (Wr) on the basis of the torque supplied to the driven wheel (Wr).